Effect of tungsten carbide reinforcement phase on the abrasive wear performance of metal matrix composites deposited by laser cladding

Abstract

Abstract One of the biggest challenges facing industrial sectors such as agriculture, mining, oil and gas, and aerospace today is issues related to component wear. In this context, the laser cladding process has often been chosen as a deposition process for abrasion resistant coatings due to the low dilution and microstructural characteristics found in the deposited material. An option for improving abrasion resistance has been the use of reinforcement phases from carbides. However, it is necessary to have a comparative study of the tribological performance of deposits made with different metallic matrices and different proportions of reinforcements. The state of the art indicates the lack of a detailed tribological study of Metal Matrix Composites (MMC) using the chemical composition of the metallic matrices in this study, as well as the high proportion of tungsten carbide (WC), as a reinforcement element, applied to the ASTM G65 standardized test. Laser processing parameters, hardness and abrasive wear performance were studied by changing the volume fraction of WC by 0, 20 and 30%Vol. in two nickel-based metallic matrices and one iron-based matrix deposited via laser cladding. The results indicate that the increase in the fraction of WC in the metallic matrix provides a smaller volumetric loss and greater resistance to abrasion reaching a volumetric loss of up to 95% lower when compared to the composite material with the matrix in its pure state. This resistance is also related to the microhardness and anchoring performance of the hard WC particles on each metallic matrix. However, there is a processability limit when using a high percentage of reinforcement phase, generating chemical and thermal reactions in the metallic matrix, causing structural defects in the deposited composite coating. In addition, the different mechanisms of abrasive wear are influenced by the hardness and the change in the chemical composition of the metallic matrix, which can lead to adhesive and brittle wear, generating greater volumetric losses during the abrasive test.